Outline

Background: Cardiovascular disease (CVD) is among the leading chronic conditions that are associated with functional limitations and disability in the aged. There is increasing evidence that even subclinical diseases such as operationalized by electrocardiogram may substantially compromise functioning. Major electrocardiogram abnormalities have been shown to be among the risk factors for increasing disability. Aim of this study was to examine the association between ECG (electrocardiographic) findings and disability status in older adults. The data used for analysis come from the KORA-Age study which is a follow-up of all participants aged 65-94 of the MONICA/KORA surveys S1 to S4. Participants were randomly selected from population registries of the study region, comprising the city of Augsburg and its two surrounding counties in Southern Germany.

Material and Methods: Disability status was measured with the Health Assessment Questionnaire-Disability Index (HAQ-DI). Participants were considered disabled if HAQ-DI>0. We estimated prevalence of disability in participants with ECG findings compared to those with normal findings. Three types of logistic models were considered: unadjusted models, models adjusted for age and sex and models adjusted for all potential confounding factors. We identified the smallest sufficient set of potential confounders with the help of a directed acyclic graph (DAG). DAG is a method to conceptualize confounding and to simplify complex multiple variable situations.

Discussion: Several ECG findings were significantly associated with disability. However, after adjusting for potential confounders, the association was no longer statistically significant. A DAG could be used to simplify the association structure in the presence of multiple intercorrelated variables. Longitudinal studies have to show if and how ECG signs are indicators or intermediate influential factors in the pathway to disability.